Boil the orzo pasta according to package directions in salted water (remember to save 1/2 cup of the pasta water). Drain, rinse well with cold water, and set aside.

Set a large skillet over medium heat and add some olive oil, the diced onion, kosher salt, pepper, and crushed red pepper flakes. Cook 4 to 5 minutes.

Add the garlic and cook another minute and add the spinach plus more kosher salt, pepper, and crushed red pepper flakes. Cook 3 to 4 minutes.

Add the cooked orzo, the reserved pasta water, another drizzle of olive oil, lemon zest, lemon juice, and half of the feta cheese. Cook 3 to 4 minutes, stirring a few times. Taste for seasoning and add more olive oil, kosher salt, pepper, olive oil, and/or lemon juice if needed.

Serve with the remaining feta cheese and toasted pine nuts or almonds over top.

Note: If the nuts didn't come already toasted, put them in a skillet over medium low with a little olive oil for a few minutes, stirring a few times, until toasted how you like.